Discontinued Operations and Divestitures (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012 Franchises DealershipLocations	Sep. 30, 2011 Franchises	Sep. 30, 2012 Franchises DealershipLocations	Sep. 30, 2011 Franchises
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of franchises (in franchises)	97		97
Number of dealership locations (in delaership locations)	77		77
Franchises, discontinued operations (in franchises)	2	4	3	15
Revenues	$ 17.8	$ 34.4	$ 70.9	$ 172.5
Cost of sales	14.9	28.6	59.3	147.2
Gross profit	2.9	5.8	11.6	25.3
Operating expenses	5.3	5.9	13.6	24.5
Impairment expenses	2.0	0	2.0	0
(Loss) income from operations	(4.4)	(0.1)	(4.0)	0.8
Other expense, net	0	0	(0.1)	(0.8)
Gain on disposition	1.0	0	1.2	27.1
(Loss) income before income taxes	(3.4)	(0.1)	(2.9)	27.1
Income tax benefit (expense)	1.3	0.1	1.1	(10.5)
Discontinued operations, net of tax	(2.1)	0	(1.8)	16.6
Sold / Closed [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Franchises, discontinued operations (in franchises)	1	3	2	14
Revenues	0	20.0	16.7	125.7
Cost of sales	0.1	16.6	14.3	107.9
Gross profit	(0.1)	3.4	2.4	17.8
Operating expenses	2.0	4.0	6.0	18.8
Impairment expenses	2.0	0	2.0	0
(Loss) income from operations	(4.1)	(0.6)	(5.6)	(1.0)
Other expense, net	0	0	0	(0.8)
Gain on disposition	1.0	0	1.2	27.1
(Loss) income before income taxes	(3.1)	(0.6)	(4.4)	25.3
Income tax benefit (expense)	1.2	0.4	1.7	(9.8)
Discontinued operations, net of tax	(1.9)	(0.2)	(2.7)	15.5
Sold [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of franchises (in franchises)	1		1
Number of dealership locations (in delaership locations)	1		1
Closed [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of franchises (in franchises)	2		2
Closed, Discontinued [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of franchises (in franchises)	1		1
Pending Disposition [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of franchises (in franchises)	1		1
Number of dealership locations (in delaership locations)	1		1
Franchises, discontinued operations (in franchises)	1	1	1	1
Revenues	17.8	14.4	54.2	46.8
Cost of sales	14.8	12.0	45.0	39.3
Gross profit	3.0	2.4	9.2	7.5
Operating expenses	3.3	1.9	7.6	5.7
Impairment expenses	0	0	0	0
(Loss) income from operations	(0.3)	0.5	1.6	1.8
Other expense, net	0	0	(0.1)	0
Gain on disposition	0	0	0	0
(Loss) income before income taxes	(0.3)	0.5	1.5	1.8
Income tax benefit (expense)	0.1	(0.3)	(0.6)	(0.7)
Discontinued operations, net of tax	(0.2)	0.2	0.9	1.1
Mid-Line Domestic Franchises [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Franchises, discontinued operations (in franchises)	0	0	0	0
Mid-Line Domestic Franchises [Member] | Sold / Closed [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Franchises, discontinued operations (in franchises)	0	0	0	0
Mid-Line Domestic Franchises [Member] | Pending Disposition [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Franchises, discontinued operations (in franchises)	0	0	0	0
Mid-Line Import Franchises [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Franchises, discontinued operations (in franchises)	1	2	1	2
Mid-Line Import Franchises [Member] | Sold / Closed [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Franchises, discontinued operations (in franchises)	0	1	0	1
Mid-Line Import Franchises [Member] | Pending Disposition [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Franchises, discontinued operations (in franchises)	1	1	1	1
Operating expenses	$ 1.0
Heavy Trucks Franchises [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Franchises, discontinued operations (in franchises)	0	0	0	10
Heavy Trucks Franchises [Member] | Sold / Closed [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Franchises, discontinued operations (in franchises)	0	0	0	10
Heavy Trucks Franchises [Member] | Pending Disposition [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Franchises, discontinued operations (in franchises)	0	0	0	0
Luxury Franchises [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Franchises, discontinued operations (in franchises)	1	2	2	3
Luxury Franchises [Member] | Sold / Closed [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Franchises, discontinued operations (in franchises)	1	2	2	3
Luxury Franchises [Member] | Pending Disposition [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Franchises, discontinued operations (in franchises)	0	0	0	0